Support postgresql url and heroku

[dukex]

To make this project heroku friendly, this PR adds some new resource configurations.

The first is the url attribute, we can easily configure the postgresql with a string like postgres://username:pass@localhost:5432/database. The typeorm already supports the the url attribute.

The second is the ssl attribute, to be possible to config SSL, this is a required option to use heroku. The typeorm already supports the the ssl attribute.

With that can have a configuration like the image